High silica faujasite polymorph - CSZ-3 and method of synthesizing

Abstract

A high silica faujasite structure, CSZ-3, has a composition 0.02 to 0.20 Cs2O: 0.80 to 0.95 Na2O: Al2O3: 5.0 to 7.0 SiO2: 2-10 H2O The zeolite has utility in sorption, separation and catalytic applications and it has high hydrothermal stability. It is made by reacting sources of silica, alumina, soda, and cesia together with a nucleating agent in the form of seeds or a seed solution, followed by hot aging at a temperature between 50 DEG and 160 DEG C.

What is claimed is: 
     
       1. A high silica faujasite aluminosilicate having a silica to alumina ratio of between 5.0 and 7.0 and having cesium ions trapped in the sodalite cages. 
     
     
       2. A high silica faujasite aluminosilicate according to claim 1, having a formula in terms of mole ratios of oxides as follows: 0.80-0.95 Na 2  O:0.02-0.20 Cs 2  O:Al 2  O 3  :5.0-7.0 SiO 2  :2-10 H 2  O. 
     
     
       3. A hydrogen exchanged high silica faujasite aluminosilicate produced by exchanging the faujasite aluminosilicate of claim 1 with an ammonium solution followed by heating so as to increase the hydrogen ion content. 
     
     
       4. A composite hydrocarbon conversion catalyst consisting of a mixture of the hydrogen exchanged faujasite aluminosilicate according to claim 3, and an amorphous inorganic oxide matrix. 
     
     
       5. A catalyst according to claim 4, wherein the amorphous matrix is a semi-synthetic mixture of silica-alumina gel and clay. 
     
     
       6. A hydrocarbon conversion catalyst made by substantially exchanging the product of claim 4 with elements of Group 2-8 of the Periodic Table. 
     
     
       7. A composite catalyst comprising the product of claim 6 combined with a Y-faujasite zeolite exchanged with cations of elements of Groups 2-8 of the Periodic Table. 
     
     
       8. A catalyst comprising about 20-25% of the hydrogen exchanged high silica faujasite aluminosilicate of claim 3, an amorphous inorganic oxide matrix, and a matrix containing about 2-5% by weight of calcined rare-earth exchanged Y-zeolite. 
     
     
       9. Sorbent compositions comprising an exchanged faujasite aluminosilicate produced by exchanging the high silica faujasite aluminosilicate of claim 2 with cations of elements of Groups 1-8 of the Periodic Table, and with or without a binder comprising clay and/or amorphous inorganic gel. 
     
     
       10. A method for preparing the high silica faujasite aluminosilicate as defined in claim 1, which comprises (a) preparing a mixture containing sources of cesia, an oxide of sodium, an oxide of silicon, an oxide of aluminum, water and sodium aluminosilicate nucleating seeds, said mixture having a final composition in terms of mole ratios of oxides within the following ranges: 1.8 to 7.0 Na 2  O:0.02 to 0.2 Cs 2  O:Al 2  O 3  :6-20 SiO 2  :90-400 H 2  O said seeds being present in an amount to yield 0.1 to 25 mole percent of the total final alumina content,   (b) mixing the composition of step (a) to obtain a homogeneous reaction mixture which forms a gel, and   (c) heating the resulting gel at a temperature over 50° C. unitl crystals are formed.   
     
     
       11. The method according to claim 10, wherein the temperature in the heating step is maintained between over 50° C. and 160° C. 
     
     
       12. The method according to claim 10, wherein the amount of reactants is controlled to obtain a final composition in the following ranges: 0.80-0.95 Na 2  O:0.02-0.20 Cs 2  O:Al 2  O 3  :5.0-7.0 SiO 2  :2-10 H 2  O. 
     
     
       13. The method according to claim 10, wherein the seeds have a composition in terms of mole ratios of oxides of about 16 Na 2  O:1-9 Al 2  O 3  :15 SiO 2  :250-2000 H 2  O. 
     
     
       14. The method according to claim 10, wherein the source of cesia added in step (a) is in the nucleating seeds. 
     
     
       15. The method according to claim 10, wherein at least some of the cesium is obtained by acid treatment of the mineral pollucite. 
     
     
       16. The method according to claim 10, wherein the seeds are present in an amount to yield 0.5 to 8 mole percent of the total final alumina content. 
     
     
       17. The method according to claim 10, further comprising adding alum to neutralize excess caustic provided by the seeds. 
     
     
       18. The method according to claim 10, further comprising adding metakaolin as a source of silica and alumina.